https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103930
Bug ID: 103930
Summary: asan intercepts fail if target library is only loaded
(indirectly) through dlopen (e.g. plugin)
Product: gcc
Version: 11.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: sanitizer
Assignee: unassigned at gcc dot gnu.org
Reporter: source at stbuehler dot de
CC: dodji at gcc dot gnu.org, dvyukov at gcc dot gnu.org,
jakub at gcc dot gnu.org, kcc at gcc dot gnu.org, marxin at
gcc dot gnu.org
Target Milestone: ---
Basically two problems:
a) the crash output is completely useless
b) asan should either reload intercept on dlopen automatically or
provide some way to trigger it
Demo: (also on https://github.com/stbuehler/asan-dlopen-intercepts-bug)
main.c:
> #include <dlfcn.h>
> #include <stdio.h>
>
> typedef void (*run_fn)();
>
> int main() {
> void *plugin = dlopen("./plugin.so", RTLD_NOW|RTLD_GLOBAL);
> run_fn fn = (run_fn) dlsym(plugin, "run");
> printf("Found plugin run function: %p\n", fn);
> (*fn)();
> }
plugin.c:
> #include <stdio.h>
> #include <crypt.h>
>
> void run() {
> char *crypted = crypt("des", "12tMnfw882VDQ");
> printf("Crypt output: %s\n", crypted);
> }
Makefile:
> override CFLAGS := -Wall -O2 -ggdb -fsanitize=address -fno-omit-frame-pointer
> # override WORKAROUND := -lcrypt
>
> all: plugin.so main
> clean:
> rm -f plugin.so main
> .PHONY: all clean
>
> plugin.so: plugin.c Makefile
> gcc -shared -o $@ -lcrypt $(CFLAGS) $<
>
> main: main.c Makefile
> gcc -o $@ -ldl $(WORKAROUND) $(CFLAGS) $<
Fails with:
> $ ./main
> Found plugin run function: 0x7fa33ea3b1a0
> AddressSanitizer:DEADLYSIGNAL
> =================================================================
> ==208926==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 (pc
> 0x000000000000 bp 0x7ffed844e1b0 sp 0x7ffed844e1a8 T0)
> ==208926==Hint: pc points to the zero page.
> ==208926==The signal is caused by a READ memory access.
> ==208926==Hint: address points to the zero page.
> #0 0x0 (<unknown module>)
>
> AddressSanitizer can not provide additional info.
> SUMMARY: AddressSanitizer: SEGV (<unknown module>)
> ==208926==ABORTING
Compiler:
> $ gcc -v
> Using built-in specs.
> COLLECT_GCC=gcc
> COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/11/lto-wrapper
> OFFLOAD_TARGET_NAMES=nvptx-none:amdgcn-amdhsa
> OFFLOAD_TARGET_DEFAULT=1
> Target: x86_64-linux-gnu
> Configured with: ../src/configure -v --with-pkgversion='Debian 11.2.0-13'
> --with-bugurl=file:///usr/share/doc/gcc-11/README.Bugs
> --enable-languages=c,ada,c++,go,brig,d,fortran,objc,obj-c++,m2 --prefix=/usr
> --with-gcc-major-version-only --program-suffix=-11
> --program-prefix=x86_64-linux-gnu- --enable-shared --enable-linker-build-id
> --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
> --libdir=/usr/lib --enable-nls --enable-bootstrap --enable-clocale=gnu
> --enable-libstdcxx-debug --enable-libstdcxx-time=yes
> --with-default-libstdcxx-abi=new --enable-gnu-unique-object
> --disable-vtable-verify --enable-plugin --enable-default-pie
> --with-system-zlib --enable-libphobos-checking=release
> --with-target-system-zlib=auto --enable-objc-gc=auto --enable-multiarch
> --disable-werror --enable-cet --with-arch-32=i686 --with-abi=m64
> --with-multilib-list=m32,m64,mx32 --enable-multilib --with-tune=generic
> --enable-offload-targets=nvptx-none=/build/gcc-11-KdLYb3/gcc-11-11.2.0/debian/tmp-nvptx/usr,amdgcn-amdhsa=/build/gcc-11-KdLYb3/gcc-11-11.2.0/debian/tmp-gcn/usr
> --without-cuda-driver --enable-checking=release --build=x86_64-linux-gnu
> --host=x86_64-linux-gnu --target=x86_64-linux-gnu
> --with-build-config=bootstrap-lto-lean --enable-link-serialization=2
> Thread model: posix
> Supported LTO compression algorithms: zlib zstd
> gcc version 11.2.0 (Debian 11.2.0-13)
